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The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

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<h4><a name = "tag_001_014_2011">&nbsp;</a>NAME</h4><blockquote>
sleep - suspend execution for an interval
</blockquote><h4><a name = "tag_001_014_2012">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

sleep <i>time</i>
</code>
</pre>
</blockquote><h4><a name = "tag_001_014_2013">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>sleep</i>
utility will suspend execution for
at least the integral number of seconds specified by the
<i>time</i>
operand.
</blockquote><h4><a name = "tag_001_014_2014">&nbsp;</a>OPTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2015">&nbsp;</a>OPERANDS</h4><blockquote>
The following operands are supported:
<dl compact>

<dt><i>time</i><dd>A non-negative decimal integer specifying
the number of seconds for which to suspend execution.

</dl>
</blockquote><h4><a name = "tag_001_014_2016">&nbsp;</a>STDIN</h4><blockquote>
Not used.
</blockquote><h4><a name = "tag_001_014_2017">&nbsp;</a>INPUT FILES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2018">&nbsp;</a>ENVIRONMENT VARIABLES</h4><blockquote>
The following environment variables affect the execution of
<i>sleep</i>:
<dl compact>

<dt><i>LANG</i><dd>Provide a default value for the internationalisation variables
that are unset or null.
If
<i>LANG</i>
is unset or null, the corresponding value from the
implementation-dependent default locale will be used.
If any of the internationalisation variables contains an invalid setting, the
utility will behave as if none of the variables had been defined.

<dt><i>LC_ALL</i><dd>
If set to a non-empty string value,
override the values of all the other internationalisation variables.

<dt><i>LC_CTYPE</i><dd>
Determine the
locale for the interpretation of sequences of bytes of text data as
characters (for example, single- as opposed to multi-byte characters
in arguments).

<dt><i>LC_MESSAGES</i><dd>
Determine the locale that should be used to affect
the format and contents of diagnostic
messages written to standard error.

<dt><i>NLSPATH</i><dd>
Determine the location of message catalogues
for the processing of
<i>LC_MESSAGES .
</i>
</dl>
</blockquote><h4><a name = "tag_001_014_2019">&nbsp;</a>ASYNCHRONOUS EVENTS</h4><blockquote>
If the
<i>sleep</i>
utility receives a SIGALRM signal, one of the following
actions will be taken:
<ol>
<p>
<li>
Terminate normally with a zero exit status.
<p>
<li>
Effectively ignore the signal.
<p>
<li>
Provide the default behaviour for signals described in the
ASYNCHRONOUS EVENTS section of
<a href="utildes.html">Utility Description Defaults</a>
<xref href=utildes></xref>.
This could include terminating with a non-zero exit status.
<p>
</ol>
<p>
The
<i>sleep</i>
utility will take the standard action for all other signals.
</blockquote><h4><a name = "tag_001_014_2020">&nbsp;</a>STDOUT</h4><blockquote>
Not used.
</blockquote><h4><a name = "tag_001_014_2021">&nbsp;</a>STDERR</h4><blockquote>
Used only for diagnostic messages.
</blockquote><h4><a name = "tag_001_014_2022">&nbsp;</a>OUTPUT FILES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2023">&nbsp;</a>EXTENDED DESCRIPTION</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2024">&nbsp;</a>EXIT STATUS</h4><blockquote>
The following exit values are returned:
<dl compact>

<dt>0<dd>The execution was successfully suspended for at least
<i>time</i>
seconds, or a SIGALRM signal was received (see
the ASYNCHRONOUS EVENTS section).

<dt>&gt;0<dd>An error occurred.

</dl>
</blockquote><h4><a name = "tag_001_014_2025">&nbsp;</a>CONSEQUENCES OF ERRORS</h4><blockquote>
Default.
</blockquote><h4><a name = "tag_001_014_2026">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2027">&nbsp;</a>EXAMPLES</h4><blockquote>
The
<i>sleep</i>
utility can be used to execute a command
after a certain amount of time, as in:
<pre>
<code>
(sleep 105; <i>command</i>) &amp;
</code>
</pre>
<p>
or to execute a command every so often, as in:
<pre>
<code>
while true
do
    <i>command</i>
    sleep 37
done
</code>
</pre>
</blockquote><h4><a name = "tag_001_014_2028">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_2029">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="wait.html">wait</a></i>,
the <b>XSH</b> specification description of
<i><a href="../xsh/alarm.html">alarm()</a></i>,
<i><a href="../xsh/sleep.html">sleep()</a></i>.
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Copyright &copy; 1997 The Open Group
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